docs: def side_by_side(left, right):
      r"""Put two boxes next to each other.
  
      Assumes that all lines in the boxes are the same width.
  
      Example:
          >>> left = 'A \nC '
          >>> right = 'B\nD'
          >>> print(side_by_side(left, right))
          A B
          C D
          <BLANKLINE>
      """
      left_lines = list(left.split('\n'))
      right_lines = list(right.split('\n'))
  
      # Pad the shorter column with whitespace
      diff = abs(len(left_lines) - len(right_lines))
      if len(left_lines) > len(right_lines):
          fill = ' ' * len(right_lines[0])
          right_lines += [fill] * diff
      elif len(right_lines) > len(left_lines):
          fill = ' ' * len(left_lines[0])
          left_lines += [fill] * diff
  
      return '\n'.join(a + b for a, b in zip(left_lines, right_lines)) + '\n'